Mayor Vincent Gray and other officials will join relatives of the victims at Sunday's groundbreaking. It comes on the 5-year anniversary of the collision between two trains near the Fort Totten station.

The crash was the deadliest in the subway system's history. In addition to the nine people killed, 80 were injured. It was caused in part by the failure of a computerized system that was supposed to keep the trains apart.

The mayor's office says the park is meant to "encourage meditation, remembrance, reflection hope and renewal" for those affected by the crash, especially the 12 children who lost parents.